This invention relates to a construction for retaining a housing block inserted in an insertion opening formed in a housing holder, the housing block having terminal receiving chambers for respectively receiving terminals each having an electric wire connected thereto.
A retaining construction for retaining a housing block inserted in an insertion opening formed in a housing holder is disclosed, for example, in Unexamined Japanese Utility Model Application No. 50-107986.
Referring to this conventional art, as shown in FIGS. 6 and 7, a plurality of housing blocks 1 are inserted respectively into juxtaposed insertion openings 3 provided in a housing holder 2, each housing block having a generally rectangular parallelepipedic contour and having terminal receiving chambers (not shown) therein.
Retaining steps 4 are formed respectively on opposed inner wall surfaces 3a at the inlet side of the insertion opening 3, and retaining projections 5 which are abutted respectively against the retaining steps 4 when the housing block 1 is inserted into the insertion opening 3 are formed respectively on the opposite side surfaces of the housing block 1, thereby limiting the housing block 1 to a predetermined insertion depth.
A retaining construction for the housing block is provided at two inner wall surfaces 3b of the insertion opening 3 disposed perpendicular to the two inner wall surfaces 3a.
The housing block-retaining construction comprises retaining lances 7 each flexible or deformable by a slit 6, and a retaining projection 8 projected from the inner surface of each retaining lance 7. A slanting surface 8a progressively increasing in height in the direction of insertion of the housing block 1, as well as a retaining surface 8b disposed substantially perpendicular to the insertion direction, is formed on the retaining projection 8.
Therefore, as the housing block 1 is inserted into the insertion opening 3, the front end of the housing block 1 is abutted against the retaining projections 8, and the retaining lances 7 are flexed and deformed to allow the insertion of the housing block 1 because the retaining projections 8 are urged. When the housing block 1 is inserted a predetermined depth with the retaining projections 5 abutted against the retaining steps 4, the rear end of the housing block 1 passes past the retaining projections 8, so that the retaining lances 7 are elastically restored to engage the retaining surfaces 8b with the rear end of the housing block 1, thereby retaining the housing block 1.
When the housing block 1 retained by the retaining lances 7 is to be taken out of the housing holder 2, a distal end portion of a tool is inserted into the inlet of the insertion opening 3, and is pushed in a direction generally perpendicular to the insertion direction to flex the two retaining lances 7, and in this condition the housing block 1 must be withdrawn. However, it is difficult to push the distal end of the tool perpendicularly to the insertion direction in the inlet of the narrow insertion opening 3, and besides the pushed tool interferes with the withdrawal of the housing block 1, and therefore withdrawal operation is quite difficult.